Background (Encyclopedia of Global Resources)
Although countless species have passed from an endangered condition to extinction throughout the history of life on Earth, the concept of “endangered species” is a human creation. After humans emigrated from their birthplace in Africa and populated large areas of Europe and Asia, they began imperiling the habitats and lives of their fellow earthlings, often to the point of extinction. With the growth of advanced industrialized societies, this rate of extinction increased. For example, during this period such creatures as the dodo, great auk, and passenger pigeon ceased to exist. Some people, such as George Perkins Marsh in his Man and Nature (1864), protested against humanity’s mindless assault on wild flora and fauna, but other scientists became enthusiastically involved in locating and exploiting the Earth’s natural resources. Conservation efforts did begin in Africa, India, and North America in the late nineteenth and early twentieth centuries, but not until the development of the modern environmental movement in the second half of the twentieth century did large numbers of people, scientists as well as laypersons, recognize the dire status of endangered species and begin to become actively engaged in their preservation.
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Nature, Quantity, and Variety of Endangered Species Resources (Encyclopedia of Global Resources)
Lawyers, landowners, businesspeople, and environmentalists have understood the term “endangered species” from their distinctive viewpoints, but scientists, striving for objectivity, have defined endangered species as undomesticated plants and animals with so few interbreeding individuals that the species faces imminent extinction in all or most of its habitat. The numbers can range from single individuals—such as “Lonesome George,” the last member of a species of Galápagos tortoise—to fewer than twenty whooping cranes in the late 1940’s, to thousands of such whale species as the blue, bowhead, humpback, and gray. When wild species have abundant but declining numbers in their ecological niches, they are often described as “threatened.” Some scientists classify species as safe, vulnerable, endangered, or critical in quantitative terms, depending on the probability of a species’ declining by a certain percentage over the subsequent fifty years. With the growth of legislation to protect threatened and endangered species, such as the Endangered Species Act (1973) in the United States, lawmakers discovered that, to save these species, they also had to protect their habitats, because they needed not only food, water, air, and light but also sites for breeding, reproduction, and rearing offspring.
Uncertainty exists about how many different life-forms now exist on...
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Agriculture and Endangered Species Resources (Encyclopedia of Global Resources)
Some scientists estimate that more than 80,000 plant species are edible, but, throughout history, humans have utilized only about 10 percent of these for food. In advanced industrialized societies, the number of species employed in commercialized agriculture was considerably smaller, about 150, and by the twenty-first century, an even smaller number, fewer then 20, had become the source of 95 percent of the world’s food. Nonedible plants also serve humankind, by purifying water, enhancing soil fertility, and moderating climate changes. Other species—such as bees, birds, and bats—have had a pivotal influence in pollinating the world’s crops. However, declines among various species of these pollinators have led scientists to search for causes and induced governments to protect the most seriously threatened. The extinctions of some species of pollinators have already caused reduced harvests of certain fruits and vegetables. Because of the mixture of wild and domesticated pollinators, placing a monetary value on these resources is difficult, though some have ventured an estimate as high as $200 million. Doubt also exists about precisely how many of the more than 100,000 pollinators are endangered, but even domesticated bee species have undergone an alarming drop in numbers that has created concern among agriculturalists. These pollinators are sometimes called keystone species because they serve an...
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Endangered Species and Medicine (Encyclopedia of Global Resources)
Throughout their history on Earth human beings have used nature as a kind of pharmacopoeia, utilizing plant and animal products to alleviate sickness and cure various diseases. For example, the bark of a willow tree was the source of a substance that reduced fever and pain (this substance later resulted in the commercial drug aspirin). Even though researchers, especially those active during and since the chemical revolution of the eighteenth century, have developed a growing number of artificial drugs that have proved increasingly effective in treating certain infectious and degenerative diseases, modern medicine continues to depend on plants and animals to provide substances that treat, and even cure, diseases directly or that serve as precursors to creating drugs that can treat or cure a variety of human ills. In the late twentieth and early twenty-first centuries, some scientists estimated that one-fourth to one-half of all medicines prescribed by doctors derive in some way from natural sources. For example, more than three million Americans who suffer from heart disease rely on digitalis, a drug derived from the purple foxglove plant. Even recent drugs often have their source in nature. Between 1998 and 2002 more than 70 percent of small-molecule drugs licensed by the U.S. Food and Drug Administration could be traced to natural sources. According to the World Health Organization, many people in developing...
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Commercial Uses of Endangered Plant and Animal Species (Encyclopedia of Global Resources)
To certain environmentalists the commercial use of endangered species is something that, for all times and under all circumstances, should be condemned. These environmentalists believe that the historical evidence is clear: Commercial overexploitation of many plant and animal species has led to their extinctions. On the other hand, certain economists point out that endangered species exist in a world of humans, whose needs for food, clothing, shelter, and work have to be taken into consideration. In such an analysis, trade-offs are inevitable. However, calculating a dollar value for endangered species has proved difficult. In general, biodiversity serves humanity in many ways, because healthy ecosystems provide the clean air and water and useful plants and animals that ultimately make human life possible. Because many plants and animals have limited commercial benefits, their ecological services tend to be undervalued. Some scientists have tried to measure the value of biodiversity quantitatively, but because of the complex interactions within ecosystems and the complex ways in which humans interact with these ecosystems, the estimates that have been made have had only limited usefulness for policy analysts.
In contrast, concrete evidence does exist about the negative effects of commercialization on endangered species. For example, passenger pigeons, despite their immense numbers in the...
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Aesthetic, Touristic, and Spiritual Benefits of Endangered Species (Encyclopedia of Global Resources)
Many conservation biologists and ecologists insist that the real values of endangered species are not extrinsic (economic or instrumental) but intrinsic (scientific, aesthetic, and spiritual). John Muir, the naturalist who once said that the best way to protect American forests was to station a soldier by every tree, felt that species protection was a deeply moral issue. Like the human species, plants and animals have the right to exist on Earth. Certain pure scientists, who believe in knowledge for knowledge’s sake, lament the disappearance of so many plants and animals before their chemical composition, structure, and functioning could be understood. Based on the knowledge gained from a selection of endangered species, the extinction of many species has resulted in the permanent loss of much valuable scientific knowledge.
More difficult to measure are the aesthetic and spiritual values of endangered species. Nevertheless, many human beings experience aesthetic pleasure in observing and taking photographs of various plants and animals. The Audubon Society and BirdLife International have as their principal purposes the conservation of all bird species, whether endangered or plentiful. Professional wildlife photographers and filmmakers often try to educate the public about the beauty of all kinds of species, both those with immediate emotional appeal and those whose...
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Context (Encyclopedia of Global Resources)
Endangered species do not exhibit the easily grasped benefits of domesticated plants and animals. Nevertheless, based on the many national and international laws that have been promulgated for their protection, endangered species constitute an important resource. Conservationists have found it relatively easy to garner public support for such charismatic megafauna as whales and grizzly bears as well as such symbolic birds as bald eagles and peregrine falcons. However, public opinion is less supportive when it comes to gray wolves, who stray from their preserves to prey on livestock, or such microflora as a rock lichen, whose ecosystem services escape most people. Endangered species have become a bone of contention between environmentalists and developers. From the perspective of environmentalists, biodiversity is a necessary condition for the health of the planet and human development. They have tried to convince businesspeople that if ecosystems fail, businesses will fail also. Furthermore, unless humans find ways to live cooperatively and sustainably with other life-forms, they will soon find themselves becoming yet another endangered species.
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Further Reading (Encyclopedia of Global Resources)
Burgess, Bonnie B. Fate of the Wild: The Endangered Species Act and the Future of Biodiversity. Athens: University of Georgia Press, 2001.
Chivian, Eric, and Aaron Bernstein, eds. Sustaining Life: How Human Health Depends on Biodiversity. New York: Oxford University Press, 2008.
Cothran, Helen, ed. Endangered Species. San Diego, Calif.: Greenhaven Press, 2001.
Dobson, Andrew P. Conservation and Biodiversity. New York: Scientific American Library, 1996.
Foreman, Paul, ed. Endangered Species: Issues and Analyses. New York: Nova Science, 2002.
Littell, Richard. Endangered and Other Protected Species: Federal Law and Regulation. Washington, D.C.: Bureau of National Affairs, 1992.
MacKay, Richard. The Penguin Atlas of Endangered Species: A Worldwide Guide to Plants and Animals. New York: Penguin Books, 2002.
Mann, Charles C. Noah’s Choice: The Future of Endangered Species. New York: Knopf, 1995.
Petersen, Shannon. Acting for Endangered Species: The Statutory Ark. Lawrence: University Press of Kansas, 2002.
Wilson, Edward O. The Future of Life. New York: Vintage Books, 2003.
International Union for Conservation of Nature. http://www.iucn.org/
U.S. Environmental Protection Agency. http://www.epa.gov/
U.S. Fish and Wildlife...
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Endangered Species (Encyclopedia of Science)
An endangered species is any animal or plant species whose very survival is threatened to the point of extinction. Once extinct, a species is no longer found anywhere on Earth. Once gone, it is gone forever.
Throughout Earth's geological history species have become extinct naturally. However, in modern times species and their natural habitats are mostly threatened by human activities. Humans have already caused the extinction of many species, and large numbers of many other species are currently endangered and may soon become extinct.
Causes of extinction and endangerment
Most of the species that have ever lived on Earth are now extinct. Extinction and endangerment can occur naturally. It can be the result of a catastrophic disturbance, such as the collision of an asteroid with Earth some 65 million years ago. The impact brought about the extinction of almost 50 percent of plant species and 75 percent of animals species then living on Earth, including the dinosaurs. Disease, a change in climate, and competition between species also can result in natural extinction.
However, since humans became Earth's dominant species, there has been a dramatic increase in the number of endangered or extinct species. The overhunting of wild animals (for their hides or meat or to protect livestock) and the destruction of natural habitats...
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